Down hole sidewall tubing valve

ABSTRACT

A system for use with a well completed with a single string of tubing to facilitate the use of PDT equipment (pump down tools). A special piston operated sleeve valve surrounds and closes a port in the lower end of the string of tubing just above a packer. The port is opened by applying pressure to the annulus between the tubing and the casing. Thus a circulating path is established down the annulus and up the tubing.

United States Patent Tulsa, Okla.

Appl. No. Filed Patented Assignee DOWN HOLE SIDEWALL TUBING VALVE Yetman Primary Examiner-Jan A. Calvert AttorneysPaul F. Hawley and John D. Gassett 103/232 166/156 l66/224X 166/224 166/224X 166/70X ABSTRACT: A system for use with a well completed with a 2 Chins 2 Dawn: single string of tubing to facilitate the use of PDT equipment U.S.Cl 166/184, (pump down tools). A special piston operated sleeve valve 166/156, 166/224 surrounds and closes a port in the lower end of the string of lnt.Cl. E21b 33/12 tubing just above a packer. The port is opened by applying Fieldof Search 1661315, pressure to the annulus between the tubing and the casing. 70, 131, 153-156, 184, 224; 137/155, 494; Thus a circulating path is established down the annulus and up 103/232, 233 the tubing.

DOWN HOLE SIDEWALL TUBING VALVE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a completion technique particularly for oil and gas wells using pump down tools. It relates especially to a system establishing a circulating path including the tubing string and annulus between the tubing string and the casing in such wells.

2. Setting of the Invention A recent development in offshore well completion is the completion of such wells where the well head assembly and production control units are positioned beneath the surface of the body of water, and preferably close to the bottom of the body of water. This is in contrast to another procedure for completing offshore wells in which a stationary platform is erected which is supported by the ocean bottom and extends to above the surface of the water. If the platform system is used, the completion procedure can be quite similar to those used on dry land or the pump down tool system may be utilized. However, when the well head assembly is placed on the ocean floor, a new set of problems is raised, especially with respect to carrying out workover operations, maintenance or other operations in a completed well. In order to carry out the routine maintenance operations within the tubing string, such as removing paraffin, installing or removing gas lift or pulling and rerunning down hole production tools, it has become necessary to develop an entirely new line of well tools which can be pumped through a production line from some remote location which may be a mile or more away. These tools enter the well by passing down the tubing string to be subsequently selectively positioned to carry out the selected operations. After completing the operation, the tool in the tubing string within the well is ordinarily removed by a reverse circulation operation. These tools and techniques are commonly called through-the-flow-line-type (TFL) operations or (PDT) equipment because they are pumped down through the production flow line string. There has been considerable literature on this type operation. Further, commercially available tools can readily be obtained, for example, from Otis Engineering Corporation, Dallas, Texas.

Although there has been considerable effort expended to date developing hydraulic pump down tools and systems, there are still certain areas where improvement is needed. One such area is in the so-called "slim hole" completions, i.e., small diameter bores having, for example, inches OD casing set therein. In these small diameter wells it is difficult to run more than one string of tubing therein. In most conventional systems for use with pump down tools, there are two strings of tubing suspended inside the casing with a crossover between the tubing strings at their lower ends. The need exists for an improved system for providing a circulating path for hydraulic fluid used with pump down tools in such slim holes. This invention provides such improved system so that pump down tools can be used in slim holes, although the invention is not limited to slim holes.

BRIEF DESCRIPTION OF THE INVENTION This invention relates to a system for use with pump down tools. A single tubing string is suspended in a well bore. A packer is placed in the annulus between the tubing string and the casing near the lower end of the tubing. A circulating port is provided in the wall of the tubing just above the packer. A spring loaded, piston operated sleeve valve surrounds this port and normally closes it. The sleeve valve is opened by applying pressure to the annulus.

Various objects and a better understanding of the invention can be had from the following description taken in conjunction with the drawings. DRAWINGS FIG. 1 is a detailed illustration of a downhole valve.

FIG. 2 illustrates the downhole valve of FIG. I suspended on the lower end of a tubing in a well bore.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, a tubing string 10 is suspended in the lower end of a casing 12. The lower end of tubing 10 is provided with a plurality of circumferentially spaced ports 14. Surrounding the lower end of tubing 10 is a housing generally designated 16. This includes a piston housing portion 18, a stern housing portion 20 and a spring housing 22.

Stem housing portion 20 is provided with a plurality of circumferentially spaced ports 24 which are at the same elevation as tubing ports 14. The housing 16 is fixed to the lower end of the tubing 10 by welding or other means.

We shall now consider the valving means mounted inside housing 16. This includes a valve stem portion 26, a piston 28 and resilient means 30 which are mounted, respectively, in stem housing 20, piston housing 18 and spring housing 22. Resilient means 30 includes springs and bellows, for example. Valve stem 26 is connected to piston 28. Valve stem 26 has a port 32. There are seals 34 and 36 on either side of port 32 between valve stem 26 and housing portion 20. Valve stem 26 is in reality a sleeve valve which encircles the tubing 10. When in the position shown in FIG. 1, valve 26 effectively closes ports 14 and 24.

We shall next consider means for opening ports 14 to the annulus 38 between the tubing 10 and casing 12. This includes piston 28 and port 21 which is in the lower end of piston housing 18. Piston 28 is provided with seals 29 and 31. When it is desired to align port 32 of the sleeve valve 26 and tubing port I4, all that is necessary to do is to apply pressure in annulus 38 so that piston 28 is driven upwardly, compressing resilient means 30. Resilient means 30 is selected so that it has enough compressive resistance to drive the piston down but not so great as to require excessive pressure in the annulus to open the valve. This drives the sleeve upwardly. Port 32 is positioned such that when piston 28 strikes shoulders 44, valve sleeve port 32 is aligned with tubing ports 14 and housing ports 24. Thus, while pressure is maintained in annulus 38, circulation can be had between the annulus 38 and the interior of tubing I0 through ports 14, 32 and 24.

Attention is next directed to FIG. 2. This figure is a partial cutaway view showing the valve open and indicating circulation between the tubing string and the annulus. This shows a packer 50 positioned below the valve mechanism. The tubing string 10 extends through packer 50. The casing 12 has perforations 62 below packer 50. When the sleeve valve 26 is closed, production can be had through perforations 26 and up through tubing 10 to the surface in a conventional manner. When it is desired to form a circulating path between the annulus 38 and the interior of the tubing 10, the well is first killed. Then pressure is applied to the annulus 38 to drive piston 28 upwardly, thus aligning port 32 of the sleeve valve 26 with the ports 14 and 24. Then circulation can be had between tubing 10 and annulus 38. Thus pump down tools can be pumped down and back out tubing 10. A seat 66, for use with pump down tools, is indicated in tubing 10 just above the valve.

While the above embodiments of the invention have been described with considerable detail, it is to be understood that various modifications of the device can be made without departing from the scope or spirit of the invention.

lclaim:

l. A system to facilitate the use of pump down tools in a well bore which comprises:

a string of tubing suspended in the casing of such well bore;

a packer closing the annulus between the lower end of the tubing string and the casing;

a tubing port in the tubing string just above the said packer;

a valve for closing said tubing port which includes a sleeve stem surrounding said tubing and having a circulating port therein;

a piston attached to the upper end of said sleeve stem;

housing means including a sleeve stem housing enclosing said sleeve stem and a piston housing surrounding said piston, said sleeve stern housing having a circulating slot adjacent the said tubing port, said circulating port of said sleeve stem when in said sleeve stems upper position being aligned with said circulating slot of said sleeve stem housing and with said tubing port, said sleeve stem in its lower position closing said housing port and said tubing P 

1. A system to facilitate the use of pump down tools in a well bore which comprises: a string of tubing suspended in the casing of such well bore; a packer closing the annulus between the lower end of the tubing string and the casing; a tubing port in the tubing string just above the said packer; a valve for closing said tubing port which includes a sleeve stem surrounding said tubing and having a circulating port therein; a piston attached to the upper end of said sleeve stem; housing means including a sleeve stem housing enclosing said sleeve stem and a piston housing surrounding said piston, said sleeve stem housing having a circulating slot adjacent the said tubing port, said circulating port of said sleeve stem when in said sleeve stem''s upper position being aligned with said circulating slot of said sleeve stem housing and with said tubing port, said sleeve stem in its lower position closing said housing port and said tubing port; resilient means in said piston housing urging said piston downwardly; port means in said piston housing below said piston such that pressure of fluid in said annulus applies an upward force to said piston.
 2. A system as defined in claim 1 including a pump down tool seating nipple inside said tubing string above said tubing port. 